England were virtually eliminated after their second defeat in Group A as the world champions dismissed them for 169 and then romped to 170 for four with 13.1 overs left.
"I'm disappointed," Flintoff said. "(But) one thing in the build-up to the game was people trying to link it to the Ashes. We took this game in isolation, as a must win game for both sides to stay in the tournament.
"The Ashes will start in three weeks time when we get to Australia."
England squandered a solid 83-run opening partnership between Andrew Strauss (56) and Ian Bell (43) and then could not cash in after reducing Australia to 34 for three on a slow pitch.
Flintoff denied England were ignoring one-day cricket after their recent success in Tests.
"I can assure you we take both forms of cricket seriously. We're a proud team, we want to win a game of cricket," he said, referring to the final Group A tie against holders West Indies.
"But we need to improve. It is an exciting time in one-day cricket over the next six months. The chance to go to Australia in the VB series, then the World Cup after that."
Flintoff said the entire team would take the blame rather than individuals.
"We're not in the business of blaming people. Australia bowled quite well in the middle period and the pitch was quite tricky to play on. We will take it collectively on our shoulders," he added.
"It is a young side, we have got a bit of inexperience. We've to step up as a team if we have the aspirations of doing well later in this winter."
